Kinematics Unit 1 Test

Question 1

Average Speed

Answer 1

the total distance covered divided by the total time taken (instant in time)

Question 2

Average Speed Formula

Answer 2

Vave =
d
–
t

Question 3

Average Velocity

Answer 3

the total displacement divided by the time interval

Question 4

Formula For AVERAGE VELOCITY:

average velocity =
displacement
———————
time taken

Answer 4

any “d” is the y-coordinate of a point from the beginning or end of a line

Vave =
d2 - d1
----------
t2 - t1
=
∆d
----
∆t

Question 5

Displacement

Answer 5

the change in position from a reference point

• vector quantity
• ->includes magnitude and direction

Question 6

Displacement Formula

Answer 6

∆d = d2 -d1

Question 7

When would you use the subtracting displacement formula?

∆d = d2 - d1

Answer 7

When there is 1 displacement or when vectors follow the same direction

EX. both vectors are going [E]
———————>——–>

Question 8

When would you use the adding displacement formula?

∆d = ∆d1 + ∆d2

Answer 8

When there is more than 1 displacement or when vectors are in different directions

Ex one vector going [W] then another traveling [E] from that last point

Question 9

Distance

Answer 9

the length of a path taken

• a scalar quantity
• ->includes magnitude only

Question 10

Instantaneous Velocity

Answer 10

the moment-to-moment measurement of an object’s velocity

Question 11

if the velocity of an object is CONSTANT…

Answer 11

then the instantaneous velocity is equal to its average velocity & equal to the SLOPE OF THE LINE on a p-t graph

Question 12

if the velocity CHANGES every moment during the motion of an object…

Answer 12

then no portion of the p-t graph is a straight line

–>p-t is made up of tangents

Question 13

How can you determine the slope of a curve?

Answer 13

each tangent on a curve has a unique slope, which represents the velocity at that instant

Question 14

What does the slope of a straight line of a p-t graph give?

What does the slope of a tangent at a point on a curved p-t graph give?

Answer 14

straight line: the velocity

tangent: the instantaneous velocity

Question 15

Magnitude

Answer 15

the number and unit of a vector

Question 16

Non-Uniform Motion

Answer 16

an object that moves through unequal displacements in equal intervals of time

Question 17

Origin

Answer 17

a main reference point

Question 18

Position

Answer 18

the location of an object relative to a reference point

• vector quantity
• ->includes magnitude, direction and a reference point

Question 19

Characteristics and Examples of Scalar Quantities

Answer 19

-only have a size and unit

2 Parts:

1. Number
2. Unit

Examples:
Distance (d) - 5m
Speed (v) - 15km/hr
Time (t) -8.0s

Question 20

Characteristics and Examples of Vector Quantities

Answer 20

-have a size, unit AND direction

3 Parts:

1. Number
2. Unit
3. Direction

Examples:
Displacement (∆d) - 5m [E]
Velocity (v) - 15km/hr [NW]
Acceleration (a) - 8m/s [FORWARD]

Question 21

What are the 3 ways motion can be described by?

Answer 21

1. A reference point
2. A magnitude (number and unit)
3. A direction

as well as certain physical characteristics such as SPEED, DISTANCE, TIME, VELOCITY, ACCELERATION etc

Question 22

Speed

Answer 22

the distance covered per unit time

• scalar quantity
• ->SI unit is m/s or km/h

Question 23

Tangent

Answer 23

a straight line that touches a curve only at one point

Question 24

Uniform Motion

Answer 24

motion with no change in direction

Question 25

Velocity

Answer 25

displacement per unit time

Question 26

To Calculate Velocity:

Answer 26

look at the slope of a position-time graph for an object in uniform motion slope = y2 - y1 ----------- x2 - x1

Question 27

Conversion to get a smaller answer: | m ---> km

Answer 27

x and y equal whatever unit of measure the question pertains to (1/x) multiplied by (1/y)

Question 28

Conversion to get a larger answer: | km ---> m

Answer 28

x and y equal whatever unit of measure the question pertains to (x/1) multiplied by (y/1)

Question 29

When are the distance and the magnitude of displacement equal, and when are they different?

Answer 29

If the object does not change direction, then the distance and displacement are equal. If the object does changes direction, then the distance and displacement are different.

Question 30

What is the difference between speed and velocity?

Answer 30

Speed is distance covered per unit time and is a scalar quantity. Velocity is displacement per unit time and is a vector quantity.

Question 31

Describe the relationship between the velocity and acceleration vectors when an object speeds up. How does this relationship change when the object slows down?

Answer 31

When the object is speeding up, the velocity and acceleration vectors have the same sign. They have different signs when the object is slowing down.

Question 32

Positive diagonal line on a POSITION-TIME graph means?

Answer 32

slope is positive: | -velocity is constant and positive

Question 33

Negative diagonal line on a POSITION-TIME graph means?

Answer 33

slope is negative: | -velocity is constant and negative

Question 34

Curved slope on a POSITION-TIME graph means?

Answer 34

-velocity is not constant as the object is undergoing acceleration

Question 35

Horizontal line on a POSITION-TIME graph means?

Answer 35

the object is stationary as the position does not change with time

Question 36

Positive diagonal line on a VELOCITY-TIME graph, in the POSITIVE QUADRANT means?

Answer 36

object is speeding up - positive velocity - positive acceleration

Question 37

Positive diagonal line on a VELOCITY-TIME graph, in the NEGATIVE QUADRANT means?

Answer 37

object is slowing down - negative velocity - positive acceleration

Question 38

Negative diagonal line on a VELOCITY-TIME graph, in the POSITIVE QUADRANT means?

Answer 38

object is slowing down (in the negative direction) - positive velocity - negative acceleration

Question 39

Negative diagonal line on a VELOCITY-TIME graph, in the NEGATIVE QUADRANT means?

Answer 39

object is speeding up (in the negative direction) - negative velocity - negative acceleration

Question 40

Horizontal line on a VELOCITY-TIME graph means?

Answer 40

the object is moving at a constant velocity - positive or negative velocity (depending on which quadrant the line is in) - zero acceleration

Question 41

Horizontal line on the X-AXIS on a VELOCITY-TIME graph means?

Answer 41

object isn't moving | -velocity is zero

Question 42

V-T GRAPH: What happens if a line crosses over the x-axis from the positive region to the negative region of the graph (or vice versa)?

Answer 42

the object has changed directions

Question 43

V-T GRAPH: how can you tell if an object is speeding up?

Answer 43

the magnitude of the velocity is increasing

Question 44

V-T GRAPH: how can you tell if an object is slowing down?

Answer 44

the magnitude of the velocity is decreasing

Question 45

Acceleration

Answer 45

rate of change of velocity per unit time

Question 46

An object undergoes acceleration if...

Answer 46

the MAGNITUDE of it's velocity changes, while its direction remains the same the DIRECTION of it's velocity changes, while its magnitude remains the same there is a change in the magnitude AND direction

Question 47

Acceleration Formula

Answer 47

a = ∆v ---- ∆t v2 - v1 --------- ∆t

Question 48

Converting a P-T graph to a V-T graph: SLOPE; HORIZONTAL LINE Which is also the same as converting a V-T to an A-T

Answer 48

1. mark each point on the P-T graph where the slope of the graph changes 2. determine the SLOPE (velocity) of each line segment 3. draw a horizontal line on the appropriate y-axis for the value of the slope, aligning the x-values to match the moments in time (s) where the velocity changes on both the P-T and V-T graph 4. wherever there is a horizontal line on the P-T, a corresponding horizontal line is drawn right on the x-axis of the V-T to show 0 velocity

Question 49

Converting a V-T graph into a P-T graph: | AREA; DIFFERENT LINE SEGMENTS

Answer 49

1. divide the area under the V-T graph into a series of sections with defined areas (triangles and rectangles 2. calculate the AREA (displacement) of each section of the V-T graph, noting in particular whether it is positive or negative 3. start off by plotting the first point (value of area1) from the V-T onto the P-T and then add the value of area2 to the value of area1 to find the next point on the P-T. Continue to do this for every point you need to plot 4. wherever there are horizontal lines on the V-T graph, use a ruler to draw straight lines on the P-T where the constant motion takes place (match the moments in time (s) on both graphs) 5. connect the remaining dots (without a ruler) 6. wherever there is a horizontal line on the x-axis of a V-T, a corresponding horizontal line is drawn the P-T to show 0 displacement